1. Department of Neurological Sciences, Multiple Sclerosis Centre, University of Catania, Italy,
2. Department of Neurological Sciences, 'La Sapienza' University, Rome, Italy
3. Department of Neurology, Multiple Sclerosis Centre, Fidenza Hospital, Italy
4. Department of Neurological Sciences, Multiple Sclerosis Centre, University of Catania, Italy
5. Medepha, Genoa, Italy